Method of transmitting and receiving carrier configuration information

ABSTRACT

A method for allowing a mobile station to reliably receive a paging message in a multi-carrier system is disclosed. A method for controlling a mobile station to receive carrier configuration information (CCI) in a wireless access system supporting multiple carriers includes a) receiving a first CCI including information about configuration of the multiple carriers from a first base station, b) receiving a second CCI including information about configuration of the multiple carriers from a second BS, and c) determining whether to perform location update and carrier switching using the first CCI and the second CCI.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2009/006888, filed on Nov. 23, 2009,which claims the benefit of earlier filing date and right of priority toKorean Application No. 10-2009-0011413, filed on Feb. 12, 2009, and alsoclaims the benefit of U.S. Provisional Application Ser. No. 61/116,644,filed on Nov. 21, 2008, the contents of which are all incorporated byreference herein in their entirety.

TECHNICAL FIELD

The present invention relates to a wireless access system for amulti-carrier environment, and more particularly to methods for allowinga mobile station to reliably receive a paging message when the mobilestation is handed over in a multi-carrier system.

BACKGROUND ART

Preferably, paging groups are large enough for a mobile station (MS) tostay most of its time within the same paging group and small enough torender paging overhead reasonable.

A paging group may include one or more base stations, and one basestation may be contained in one or more paging groups. The paging groupsmay be defined in a management system. A paging group may use a paginggroup-action backbone network message. In addition, a paging controlleruses another backbone message (paging-announce message), to manage thelist of mobile stations in an idle mode and initiate paging of a mobilestation on all base stations belonging to a paging group.

DISCLOSURE OF INVENTION Technical Problem

Accordingly, the present invention is directed to a method fortransmitting and receiving carrier configuration information thatsubstantially obviates one or more problems due to limitations anddisadvantages of the related art.

An object of the present invention devised to solve the problem lies ona reliable communication method for a multi-carrier environment.

Another object of the present invention devised to solve the problemlies on a method for allowing a mobile station to receive a pagingmessage by effectively utilizing carriers in a multi-carrierenvironment.

Another object of the present invention devised to solve the problemlies on a method for enabling an idle mode mobile station (MS) havingmoved to a neighbor cells supporting different carriers to update itslocation by switching a carrier to another carrier.

A further object of the present invention devised to solve the problemlies on a method for enabling an idle mode MS to receive a pagingmessage using carrier configuration information.

Technical Solution

In order to solve the above-mentioned technical problems, the presentinvention provides a method for enabling an MS to reliably receive apaging message when the MS is handed over in a multi-carrier system, andthe MS for use in the same.

The object of the present invention can be achieved by providing amethod for controlling a mobile station to receive carrier configurationinformation (CCI) in a wireless access system supporting multiplecarriers, the method including a) receiving a first CCI includinginformation about configuration of the multiple carriers from a firstbase station, b) receiving a second CCI including information aboutconfiguration of the multiple carriers from a second BS, and c)determining whether to perform location update and carrier switchingusing the first CCI and the second CCI.

The first CCI and the second CCI each may include at least one ofconfiguration information of the multiple carriers supplied from thefirst base station and the second base station.

The first CCI and the second CCI may include indexes of the multiplecarriers and a paging group ID supported by each of the multiplecarriers.

The method may further include performing, by the mobile station,location update to the second base station, when the second base stationdoes not provide a paging group ID assigned to the mobile station.

The method may further include performing, by the mobile station,carrier switching to one of the multiple carriers supplied from thesecond base station, when the second base station does not provide thecarrier currently used by the mobile station.

The first CCI and the second CCI may be transmitted using one of abroadcast channel (BCH), a mobile neighbor BS advertisement(MOB_NBR-ADV) message, and a system information message.

The first CCI and the second CCI may be transmitted using one of aranging response (RNG-RSP) message, a registration response (REG-RSP)message, and a basic capability response (SBC-RSP) message.

The method may further include receiving a super frame header includinga first field indicating a frame via which a system information messageincluding the first CCI is transferred from the first base station, andreceiving a super frame header including a second field indicating aframe via which a system information message including the second CCI istransferred from the second base station, wherein the receiving step a)is performed at the frame indicated by the first field, and thereceiving step b) is performed at the frame indicated by the secondfield.

In another aspect of the present invention, provided herein is a methodfor controlling a serving base station to receive carrier configurationinformation (CCI) in a wireless access system supporting multiplecarriers including transmitting a super frame header including a fieldindicating a frame via which a message including the CCI is transferred,transmitting the message including the CCI via the frame indicated bythe field, wherein the CCI includes indexes of the multiple carriers anda paging group ID supported by each of the multiple carriers.

The CCI may include configuration information of the multiple carriersabout at least one of the serving base station and the neighboring basestation. The message may be one of a broadcast channel (BCH) and asystem information message.

In another aspect of the present invention, provided herein is a mobilestation for a wireless access system supporting multiple carriersincluding a receiver for receiving an external radio signal, and aprocessor, wherein the receiver receives first carrier configurationinformation (CCI) including information about configuration of themultiple carriers from a first base station, and receives second CCIincluding information about configuration of the multiple carriers froma second BS, and the processor determines whether to perform locationupdate and carrier switching using the first CCI and the second CCI.

The first CCI and the second CCI may include indexes of the multiplecarriers and a paging group ID supported by each of the multiplecarriers.

The processor may perform location update to the second base stationwhen the second base station does not provide a paging group ID assignedto the mobile station.

The processor may perform carrier switching to one of the multiplecarriers supplied from the second base station when the second basestation does not provide the carrier currently used by the mobilestation.

The receiver receives a super frame header including a first field,indicating a frame via which a system information message including thefirst CCI is transferred, from the first base station. In addition, thereceiver receives a super frame header including a second field,indicating a frame via which a system information message including thesecond CCI is transferred, from the second base station. In this case,the first CCI is received at the frame indicated by the first field, andthe second CCI is received at the frame indicated by the second field.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present invention are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present invention could achieve will be more clearlyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings

Advantageous Effects

Exemplary embodiments of the present invention have the followingeffects.

First, the present invention can provide a multi-carrier environmentwith reliable communication.

Second, the present invention uses carrier configuration information inthe multi-carrier environment such that the MS can effectively receive apaging message.

Third, if an idle mode MS moves to a neighbor cell supporting differentcarriers in the multi-carrier environment, the present invention enablesthe idle mode MS to update its location by switching a carrier toanother carrier.

It will be appreciated by persons skilled in the art that that theeffects that could be achieved with the present invention are notlimited to what has been particularly described hereinabove and otheradvantages of the present invention will be more clearly understood fromthe following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 is a flowchart illustrating a paging procedure in an Institute ofElectrical and Electronics Engineers (IEEE) 802.16 system which is awireless access system.

FIG. 2 is a flowchart illustrating a method for transmitting carrierconfiguration information according to one embodiment of the presentinvention.

FIG. 3 is a flowchart illustrating a method for transmitting carrierconfiguration information according to another embodiment of the presentinvention.

FIG. 4 is a structural diagram illustrating a super-frame structure towhich the method for transmitting carrier configuration information isapplied according to one embodiment of the present invention.

FIG. 5 is a structural diagram illustrating a super-frame structure towhich the method for transmitting carrier configuration information isapplied according to another embodiment of the present invention.

FIG. 6 is a flowchart illustrating a method for transmitting carrierconfiguration information according to yet another embodiment of thepresent invention.

FIG. 7 is a flowchart illustrating a carrier switching method accordingto another embodiment of the present invention.

FIG. 8 is a conceptual diagram illustrating a method for enabling anidle mode MS to receive a paging message when the idle mode MS movesbetween base stations (BSs) supporting multiple carriers (multi-carrier)according to another embodiment of the present invention.

FIG. 9 is a conceptual diagram illustrating a method for enabling anidle mode MS to receive a paging message when the idle mode MS movesbetween base stations (BSs) supporting multiple carriers (multi-carrier)according to another embodiment of the present invention.

FIG. 10 is a conceptual diagram illustrating a method for enabling anidle mode MS to receive a paging message when the idle mode MS movesbetween base stations (BSs) supporting multiple carriers (multi-carrier)according to yet another embodiment of the present invention.

FIG. 11 is a conceptual diagram illustrating a method for enabling anidle mode MS to receive a paging message when the idle mode MS movesbetween base stations (BSs) supporting multiple carriers (multi-carrier)according to yet another embodiment of the present invention.

FIG. 12 is a block diagram illustrating an example of a transmitter anda receiver according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.

The present invention relates to a wireless access system. Moreparticularly, the present invention relates to methods for enabling amobile station (MS) to reliably receive a paging message when the MS ishanded over in a multi-carrier system.

Exemplary embodiments described hereinbelow are combinations of elementsand features of the present invention. The elements or features may beconsidered selective unless otherwise mentioned. Each element or featuremay be practiced without being combined with other elements or features.Further, an embodiment of the present invention may be constructed bycombining parts of the elements and/or features. Operation ordersdescribed in embodiments of the present invention may be rearranged.Some constructions of any one embodiment may be included in anotherembodiment and may be replaced with corresponding constructions ofanother embodiment.

In the description of drawings, procedures or steps, which may ruin thesubstance of the present invention, are not explained. And, proceduresor steps, which can be understood by those skilled in the art, are notexplained as well.

In exemplary embodiments of the present invention, a description is madeof a data transmission and reception relationship between a Base Station(BS) and an MS. Herein, the term BS refers to a terminal node of anetwork, which communicates directly with the MS. In some cases, aspecific operation described as performed by the BS may be performed byan upper node of the BS.

Namely, it is apparent that, in a network comprised of a plurality ofnetwork nodes including a BS, various operations performed forcommunication with an MS may be performed by the BS, or network nodesother than the BS. The term BS may be replaced with the term fixedstation, Node B, eNode B (eNB), access point, etc. The term MS may bereplaced with the term User Equipment (UE), Subscriber Station (SS)Mobile Subscriber Station (MSS), Advanced MS (AMS), mobile terminal,etc.

A transmitter means a node that transmits voice or data service and areceiver means a node that receives voice or data service. Hence, an MSmay be a transmitter and a BS may be a receiver, on an uplink. Likewise,the MS may be a receiver and the BS may be a transmitter, on a downlink.

Meanwhile, the MS may be any of a Personal Digital Assistant (PDA), acellular phone, a Personal Communication Service (PCS) phone, a GlobalSystem for Mobile (GSM) phone, a Wideband Code Division Multiple Access(WCDMA) phone, a Mobile Broadband System (MB S) phone, etc.

Exemplary embodiments of the present invention may be achieved byvarious means, for example, hardware, firmware, software, or acombination thereof.

In a hardware configuration, methods according to exemplary embodimentsof the present invention may be achieved by one or more ApplicationSpecific Integrated Circuits (ASICs), Digital Signal Processors (DSPs),Digital Signal Processing Devices (DSPDs), Programmable Logic Devices(PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers,microcontrollers, and/or microprocessors.

In a firmware or software configuration, the methods according to theexemplary embodiments of the present invention may be implemented in theform of a module, a procedure, a function, etc. performing theabove-described functions or operations. A software code may be storedin a memory unit and executed by a processor. The memory unit is locatedat the interior or exterior of the processor and may transmit andreceive data to and from the processor via various known means.

Exemplary embodiments of the present invention are supported by standarddocuments disclosed for at least one of wireless access systemsincluding Institute of Electrical and Electronics Engineers (IEEE) 802systems, 3^(rd) Generation Project Partnership (3GPP) systems, 3GPP LongTerm Evolution (LTE) systems, and 3GPP2 systems. In particular, thesteps or parts, which are not described to clearly reveal the technicalidea of the present invention, in the exemplary embodiments of thepresent invention may be supported by the above documents. Allterminologies used herein may be supported by at least one ofP802.16-2004, P802.16e-2005, and P802.16Rev2 documents which describethe standards of IEEE 802.16.

Specific terms used in the following description are provided to helpthe understanding of the present invention. These specific terms may bereplaced with other terms within the scope and spirit of the presentinvention.

It is assumed that the following embodiments use a multi-carrier scheme.Therefore, a mobile station (MS) and a base station (BS) can effectivelycommunicate with each other using a plurality of carriers. The followingembodiments of the present invention may also be applied to otherwireless access technologies other than the IEEE 802.16e/m network(and/or 3GPP LTE).

In the following embodiments of the present invention, a primary carrierand a secondary carrier are defined. The MS may communicate with the BSusing one primary carrier and several secondary carriers.

In the embodiments of the present invention, for convenience ofdescription and better understanding of the present invention, a carriercapable of transmitting and receiving control information and data isdefined as a Fully Configured Carrier (FCC), and another carrier capableof transmitting and receiving some parts of the control information anddata is defined as a Partially Configured Carrier (PCC).

In this case, the primary carrier may be defined as an FCC, and thesecondary carrier may be defined as an FCC or a PCC. Generally, the MScan acquire all control information and information of subcarriers usingthe primary carrier. In addition, the MS and the BS can transmit andreceive data using the secondary carrier. In the embodiments of thepresent invention, a Fully Configured Secondary Carrier (FCSC)established in a specific MS may be established as a primary carrier ofanother MS.

FIG. 1 is a flowchart illustrating a paging procedure in an IEEE 802.16system which is a wireless access system.

In an idle mode, paging may be performed on a paging group basis. Forinstance, an MS may be a member of one or more paging groups. In eachpaging group, upon receipt of an incoming call for an MS or a packetdirected to the MS from an external network, a paging controller pagesthe MS to detect it. For the paging, specifically, the paging controllermay transmit a paging message to all BSs within the paging group and,upon receipt of the paging message, each BS broadcasts a Mobile PagingAdvertisement (MOB_PAG-ADV) message to MSs.

Referring to FIG. 1, an MS transmits a Mobile Deregistration Request(MOB_DREG-REQ) message to a serving BS to transition from normal mode toidle mode at step S101.

Upon receipt of the MOB_DREG-REQ message, the serving BS may transmitand receive serving BS information and MS information to and from apaging controller at step S102. Specifically, the serving BS may notifythe paging controller of an Identifier (ID) of the MS that intends toenter the idle mode and an ID of the serving BS. The PC may transmit apaging group ID or an ID of the paging controller to the serving BS. Thepaging group ID or the paging controller ID may be used for transmissionand reception of a paging message at step S102.

The serving BS may a Mobile Deregistration Command (MOB_DREG-CMD)message to the MS in response to the MOB_DREG-REQ message at step S103.The MOB_DREG-CMD message may include paging information (e.g. a pagingcycle, a paging offset, and a paging listening interval). TheMOB_DREG-CMD message may further include the paging controller ID andthe paging group ID.

Upon receipt of the MOB_DREG-CMD message, the MS enters the idle mode atstep S104. The MS may receive a paging message based on the paginginformation received by the MOB_DREG-CMD message. During a paginglistening interval, the MS may monitor a radio channel to determinewhether there is a paging message directed to it. The MS may operate insleep mode during the remaining time periods, thereby saving batterypower.

At step S105, the paging controller may receive an incoming call or anexternal packet that is transmitted from an external network to the MS.

Then the paging controller may perform a paging procedure for searchingfor the MS upon receipt of the incoming call or external packet. At stepS106, the paging controller transmits a paging message to all BSs of thepaging group.

Upon receipt of the paging message, the BSs of the paging groupbroadcast a Mobile Paging Advertisement (MOB_PAG-ADV) message to theirmanaged MSs at step S107.

The MS checks the MOB_PAG-ADV message and if the paging controller haspaged the MS, it may enter a normal mode at step S108 and communicatewith the serving BS at step S109.

The above-mentioned messages and procedures of FIG. 1 may also beapplied to the following embodiments of the present invention.

1. Method for transmitting Carrier Configuration Information (CCI)

A variety of methods for transmitting carrier configuration information(CCI) will hereinafter be described in detail. Specifically, the CCI mayhelp an MS in an idle mode to switch a carrier to another carrier sothat the MS of the idle mode can reliably receive a paging message usingthe switched carrier.

FIG. 2 is a flowchart illustrating a method for transmitting carrierconfiguration information according to one embodiment of the presentinvention.

FIG. 2 shows an example of a method for transmitting carrierconfiguration information using a broadcast message. At steps S210 andS220, a serving BS may periodically or non-periodically a BroadcastChannel (BCH) or MOB_NBR-ADV message including the serving BS's CCIand/or the neighbor BS's CCI to the MS.

The following table 1 shows an exemplary format of a CCI.

TABLE 1 Fully Configured Carrier Index PG ID Carrier 1 Paging Group IDsupported by Carrier 1 Carrier 2 Paging Group ID supported by Carrier 2Carrier 3 Paging Group ID supported by Carrier 3 ~ ~ Carrier N PagingGroup ID supported by Carrier N

If the MS decodes the CCI, it can recognize not only indexes of carrierssupported by respective paging groups of a multi-carrier system but alsoinformation of paging group IDs supported by respective carriers.

The following table 2 shows a BCH or system information format includinga CCI.

TABLE 2 Size Syntax (Bit) Notes BCH( ) or Additional — — systeminformation( ) { ~ BS ID Serving BS ID N_Fully_configured_Carrier Thenumber of Fully Configured Carriers supported by Serving BS ID For(i=0;i< N_Fully_configured_Carrier; i++) { Fully_Configured_Carrier ServingBS s ID Fully_Configured_Carrier ID Paging Group ID Paging Group IDsupported by Fully Configured Carrier of Serving BS } // End of servingBS

Fully configured carrier in- formation N_Neighbor Total number ofNeighbor base station For(i=0; i< N_Neighbor; Neighbor Cell Carrier Con-i++) { figuration Information BS ID Neighbor BS IDN_Fully_Configured_Carriers Total number of Fully Configured CarriersFor(i=0; i<N_(——)Fully_Configured_Carriers; i++) {Fully_Configured_Carrier Fully_Configured_Carrier ID ID Paging Group IDPaging Group ID supported by corresponding Fully Configured Carrier } //End of Carrier con- figuration information } // End of For(i=0; i<N_Neighbor; i++) ~ } //End of BCH( ) or Ad- ditional system in-formation( )

Table 2 shows an exemplary case in which the serving BS CCI and theneighbor BS CCI are contained in a BCH. Referring to FIG. 2, the BCH mayinclude a ‘BS ID’ field indicating an ID of a serving BS, a‘N_Fully_configured_Carrier’ field indicating the number of FCCssupported by the serving BS, an ‘Fully_Configured_Carrier ID’ fieldindicating IDs of FCCs supported by the serving BS, and a ‘Paging GroupID’ field indicating an ID of a paging group supported by an FCC of theserving BS.

In addition, the BCH may further include an ‘N_Neighbor’ fieldindicating the total number of neighbor BSs, a ‘BS ID’ field indicatingan ID of a neighbor BS, an ‘N_Fully_Configured_Carriers’ fieldindicating the total number of FCCs supported by a neighbor BS, a fieldindicating FCCs supported by a neighbor BS, and a ‘Paging Group ID’field indicating an ID of a paging group supported by an FCC of aneighbor BS.

Although Table 2 has disclosed the CCI contained in the BCH, the CCI mayalso be contained in additional system information. The additionalsystem information is an example of system information.

The following table 3 shows an example of a mobile neighbor BSadvertisement (MOB_NBR_ADV) message including CCI.

TABLE 3 Size Syntax (Bit) Notes MOB_NBR-ADV( ) { — — ~ N_Neighbor Totalnumber of Neighbor For(i=0; i< N_Neighbor; i++) { BS ID Neighbor BS IDN_Fully_Configured_Carriers Total number of Fully Configured CarriersFor(i=0; i<N_(——)Fully_Configured_Carriers; i++) {Fully_Configured_Carrier Fully_Configured_Carrier ID ID Paging Group IDPaging Group ID supported by corresponding Fully Configured Carrier } //End of Carrier con- figuration information } // End of For(i=0; i<N_Neighbor; i++) ~ } //End of NBR-ADV( )

Referring to FIG. 3, the MOB_NBR-ADV message may include an ‘N_neighbor’field indicating the total number of neighbor BSs, a ‘BS ID’ fieldindicating a neighbor BS ID, an ‘N_Fully_Configured_Carriers’ fieldindicating the total number of FCCs supported by a neighbor BS, a‘Fully_Configured_Carrier ID’ field indicating IDs of FCCs supported bya neighbor BS, and a ‘Paging Group ID’ field indicating a paging groupID supported by each FCC.

FIG. 3 is a flowchart illustrating a method for transmitting carrierconfiguration information according to another embodiment of the presentinvention.

The BS may transmit CCI to an MS using additional system information.Referring to FIG. 3, the BS may transmit a Start Frame Number (SFN)field or a Start SubFrame Number (SSFN) field to the MS at step S310. Inthis case, the SFN field indicates a number of a frame at whichadditional system information is transferred, and the SSFN fieldindicates a number of a subframe at which such additional systeminformation is transferred. For example, the BS may transmit a SuperFrame Header (SFH) including the SFN or SSFN field to the MS.

At step S320, the BS may transmit additional system informationincluding the CCI to the MS at a frame indicated by the SFN field or asubframe indicated by the SSFN field. Also, the MS may acquire CCI bydecoding a frame corresponding to the SFN or a subframe corresponding tothe SSFN.

FIG. 4 is a structural diagram illustrating a super-frame structure towhich the method for transmitting carrier configuration information(CCI) is applied according to one embodiment of the present invention.

Referring to FIG. 4, a super-frame for use in the IEEE 802.16m systemhas a size of 20 ms and may include one or more frames. In this case, itis preferable that one superframe be composed of 4 frames, each of whichhas a size of 5 ms. One frame includes one or more subframes.Preferably, 8 subframes may be contained in one frame.

The BS may transmit a Super-Frame Header (SFH) at a first frame (Frame#0) of each super-frame. That is, the BS may transmit the SFH includingthe SFN field to the MS at a first subframe of the first frame (Frame#0). In this case, the SFN field may indicate a frame or subframe atwhich additional system information including the CCI is transferred.

In one embodiment of the present invention, it is assumed thatadditional system information is transferred at a third frame (Frame#2). Therefore, the SFN may indicate the third frame (Frame #2), and theMS may decode additional system information at the third frame (Frame#2). In this case, the additional system information may further includea paging group ID (PG ID) and a paging indicator in addition to the CCI.

FIG. 3 is a flowchart illustrating a method for transmitting CCI usingadditional system information, and FIG. 4 is a structural diagramillustrating a frame for transmitting CCI using such additional systeminformation. In a modified example of the embodiments shown in FIGS. 3and 4, the BS may transmit the CCI using the BCH. In this case, the BSmay include the CCI in only a specific BCH instead of all BCHsdifferently from FIG. 2, and transmit the specific BCH including the CCIto the MS. Therefore, overall system load can be greatly reduced ascompared to the case in which the CCI is contained in each of all BCHsand transmitted.

FIG. 5 is a structural diagram illustrating a super-frame structure towhich the method for transmitting carrier configuration information(CCI) is applied according to another embodiment of the presentinvention.

The super-frame structure shown in FIG. 5 is similar to that of FIG. 4.However, FIG. 5 shows a method for transmitting the CCI to the MS at afixed specific frame or subframe without using the SFN field in adifferent way from FIG. 4. In FIG. 5, it is assumed that the MS is in anidle mode, so that a procedure for allowing the MS to enter the idlemode may also refer to FIG. 1.

Referring to FIG. 5, the BS may transmit additional system informationto the MS at a first downlink (DL) subframe at which a paging listeninginterval of the MS begins. The MS is woken up from the paging listeninginterval, and decodes a first DL subframe, such that it can acquire a PGID, a paging indicator and CCI contained in additional systeminformation.

In FIG. 5, it is assumed that the paging listening interval of the MSstarts from a third frame (Frame #2). Therefore, the MS in the idle mode(idle mode MS) is woken up from the third frame, and decodes additionalsystem information, such that it can acquire CCI.

If the additional system information is large in size so that the BS isunable to transmit all data at one DL subframe, the BS can continuouslytransmit additional system information at the next DL subframe.

FIG. 6 is a flowchart illustrating a method for transmitting carrierconfiguration information (CCI) according to another embodiment of thepresent invention.

The BS may transmit the CCI to the MS at an initial network entryprocess. In other words, the BS may transmit the CCI to the MS using aranging response (RNG-RSP) message, a registration response (REG-RSP)message, and /or a basic capability response (SBC-RSP) message.

Referring to FIG. 6( a), the MS may transmit the SBC-REQ message fornegotiating basic performance to the BS at the initial network entryprocess at step S610.

The BS may transmit the SBC-RSP message to the MS in response to theSBC-REQ message at step S630. In this case, the BS includes CCI in theSBC-RSP message, and transmits the resultant SBC-RSP message includingthe CCI to the MS. Therefore, the MS decodes the CCI contained in theSBC-RSP message, so that it can recognize multi-carriers supported by acurrent serving BS and/or a neighbor BS.

The following table 4 shows an example of the SBC-RSP message for use inembodiments of the present invention.

TABLE 4 Size Syntax (Bit) Notes SBC-RSP( ) { — — ~N_Fully_Configured_Carriers Total number of Fully Configured CarriersFor(i=0; i<N_Fully_Configured_Carriers; i++) { Fully_Configured_CarrierFully_Configured_Carrier ID ID Paging Group ID Paging Group ID supportedby corresponding Fully Configured Carrier } ~ } //End of SBC-RSP( )

Referring to Table 4, the SBC-RSP message may include an‘N_Fully_Configured_Carriers’ field indicating the total number of FCCs,a ‘Fully_Configured_Carrier’ field indicating IDs of FCCs supported by aBS, and a ‘Paging Group ID’ field indicating a paging group (PG) IDsupported by a corresponding FCC.

Referring to FIG. 6( b), the MS may transmit a ranging request (RNG-REQ)message to the BS so as to perform a ranging procedure in variousranging processes at step S620.

The BS may transmit a ranging response (RNG-RSP) message to the MS inresponse to the RNG-REQ message at step S640. In this case, the BSincludes CCI in the RNG-RSP message, and transmits the resultant RNG-RSPmessage including the CCI to the MS. Accordingly, the MS decodes the CCIcontained in the RNG-RSP message, so that it can recognizemulti-carriers supported by a current serving BS and/or a neighbor BS.

In another aspect of the present invention, the MS may transmit aregistration request (REG-REQ) message to the BS at the initial networkentry process at step S620, so that the MS can be registered to the BSby the REG-REQ message.

In response to the REG-REQ message, the BS may transmit the REG-RSPmessage including the CCI to the MS at step S640. Therefore, the MSdecodes the CCI of the RNG-RSP message, such that it can recognizemulti-carriers supported by a current serving BS and/or a neighbor BS.

The following table 5 shows an example of the SBC-RSP message for use inembodiments of the present invention.

TABLE 5 Size Syntax (Bit) Notes RNG-RSP( )/REG-RSP( ) { — — ~N_Fully_Configured_Carriers Total number of Fully Configured CarriersFor(i=0; i<N_(——)Fully_Configured_Carriers; i++) {Fully_Configured_Carrier Fully_Configured_Carrier ID ID Paging Group IDPaging Group ID supported by corresponding Fully Configured Carrier } ~} //End of SBC-RSP( )

Referring to Table 5, a ranging response (RNG-RSP) message and/or theregistration response (REG-RSP) message may include an‘N_Fully_Configured_Carriers’ field indicating the total number of FCCs,a ‘Fully_Configured_Carrier’ field indicating IDs of FCCs supported by aBS, and a ‘Paging Group ID’ field indicating a paging group (PG) IDsupported by a corresponding FCC.

2. Method for performing Location Update and Carrier Switching inMulti-Carrier System

The method for performing location update and carrier switching in theabove-mentioned multi-carrier system may be applicable to theabove-mentioned embodiments shown in FIGS. 1 to 6.

FIG. 7 is a flowchart illustrating a carrier switching method accordingto another embodiment of the present invention.

In FIG. 7, it is assumed that the MS is in the idle mode as in FIG. 1.That is, the MS may enter the idle mode through steps of FIG. 1 at stepS710.

A Serving Base Station (SBS) can transmit the CCI to the MS using themethods shown in FIGS. 2 to 6. In FIG. 7, the BS may transmit abroadcast channel (BCH) including the CCI to the MS at step S720.

The MS in an idle mode may move to a cell area of a Neighboring BaseStation (NBS) at step S730.

After the MS moved to the cell area of the NBS, the MS can receive theBCH including the CCI at the NBS. In other words, the NBS may broadcastthe BCH including the CCI periodically or whenever a specific conditionis satisfied at step S740.

The MS decodes the BCH received from the NBS, such that it can recognizea multi-carrier ID and paging group ID supported by the NBS. The MSrecognizes the paging group ID of the NBS such that it can determinewhether the BS belongs to the same paging group as that of the SBS. Inaddition, the MS recognizes the multi-carrier ID such that it candetermine whether the multi-carrier currently used by the MS issupported by the NBS at step S750.

Meanwhile, in the case where the paging group (PG) ID of the NBS isequal to that of the SBS and the NBS also provides the multi-carriercurrently used by the MS, the MS can receive the paging message receivedfrom the NBS at step S760. At this time, in the case where the PG ID ofthe SBS is equal to that of the NBS and the NBS does not provide themulti-carrier currently used by the MS, the MS can receive a pagingmessage from the NBS by performing carrier switching.

On the other hand, if the PG ID of the SBS is different from that of theNBS, the MS can perform location update to the NBS at step S770.Needless to say, the MS may simultaneously perform the location updateand the carrier switching according to the above-mentioned conditions.

The embodiment shown in FIG. 7 may also be applied to the followingembodiments of FIGS. 8 to 11.

FIG. 8 is a conceptual diagram illustrating a method for enabling anidle mode MS to receive a paging message when an idle mode MS movesbetween BSs supporting multiple carriers (multi-carrier) according toanother embodiment of the present invention.

Referring to FIG. 8, the idle mode MS is assigned a PG ID (A) from aserving BS (BS 1). The MS may receive a BCH including CCI from theserving BS (BS 1) periodically or whenever a specific condition issatisfied. In this case, multi-carriers used by the serving BS (BS 1)may include an FCC 1 for supporting the PG ID (A), an FCC 2 forsupporting a PG ID (B), an FCC 3 for supporting a PG ID (C), etc.

The idle mode MS may move between BSs supporting multiple carriers. Thatis, the MS may move from the serving BS (BS 1) to the neighboring BS (BS2). FIG. 8 is a conceptual diagram illustrating an exemplary case inwhich the MS moves to a neighboring BS having a carrier (FCC 1)supporting the PG ID (A) of the MS.

After the idle mode MS has moved to the NBS (BS 2), it can receive theBCH having the CCI from the NBS (BS 2) during a paging listeninginterval. The MS recognizes the CCI that has been transmitted from theNBS (BS 2) (See Tables 1 and 2), such that it can acquire information ofmulti-carriers supplied from the NBS (BS 2). In other words, the MS canrecognize PG IDs supported by a Fully Configured Carrier (FCC) of theNBS (BS 2). In this case, multi-carriers used by the BS 2 may include anFCC 1 supporting a PG ID (A), an FCC 2 for supporting a PG ID (B), anFCC 3 for supporting a PG ID (C), etc.

Therefore, since the neighboring BS NBS (BS 2) supports the same PG IDas the PG ID (A) of the MS, the MS may not perform location update tothe NBS (BS 2). In addition, the BS 2 provides the FCC 1, and the FCC 1supports the PG ID (A). That is, the BS 2 also provides the FCC 1currently used by the MS, the MS may not perform carrier switching asnecessary. Namely, the MS can continuously receive a paging messagethrough the current FCC 1.

FIG. 9 is a conceptual diagram illustrating a method for enabling anidle mode MS to receive a paging message when the idle mode MS movesbetween BSs supporting multiple carriers according to another embodimentof the present invention.

Multi-carriers supplied from the SBS (BS 1) are equal to those of FIG.8. However, multi-carriers supplied from the NBS (BS 2) may be differentfrom those of the SBS (BS 1). That is, the NBS (BS 2) assumes that an MSin an idle mode does not support the FCC 1 assigned to the idle mode MS.Therefore, the MS may perform carrier switching so as to receive an idlemode service.

Referring to FIG. 9, a PG ID assigned to the MS is a PG ID (A), and theMS may move from the SBS (BS 1) to the NBS (BS 2). The MS may receive aBCH including CCI from the BS 2 during the paging listening interval.Therefore, the MS recognizes the CCI of the BS 2 (See Tables 1 and 2),such that it can recognize PG IDs of FCCs supplied from the BS 2.

However, the BS 2 provides an FCC that supports the same PG ID (A) as inthe MS, but the FCC2 supports the PG ID (A) at the NBS (BS 2).Therefore, the MS may switch its own carrier to the FCC2 supporting thePG ID (A). That is, the MS may receive a paging message using the FCC 2in a cell area of the NBS (BS 2).

FIG. 10 is a conceptual diagram illustrating a method for enabling anidle mode MS to receive a paging message when the idle mode MS movesbetween base stations (BSs) supporting multiple carriers (multi-carrier)according to yet another embodiment of the present invention.

Multi-carriers supplied from the SBS (BS 1) are equal to those of FIG.8. Also, multi-carriers supplied from the NBS (BS 2) may be equal tothose of the SBS (BS 1). However, it is assumed that the FCC 1 suppliedfrom the NBS (BS 2) provides a PG ID (B) instead of a PG ID (A).

The PG ID assigned to an idle mode MS is the PG ID (A), and the idlemode MS may move from the BS 1 to the BS 2. The MS may receive a BCHincluding CCI from the BS 2 during the paging listening interval.Therefore, the MS recognizes the CCI of the BS 2 (See Tables 1 and 2),such that it can recognize PG IDs of FCCs supplied from the BS 2.

In FIG. 10, the BS 2 provides an FCC 1, an FCC 2, and an FCC 3. The FCC1 of the BS 2 supports the PG ID (B), the FCC 2 supports the PG ID (C),and the FCC 3 supports the PG ID (D). That is, the BS 2 provides the FCC1 and does not provide services related to the PG ID (A).

Therefore, the BS 2 does not provide the FCC supporting the PG ID (A),so that it can perform location update to the BS 2. That is, the MS mayswitch its own paging group to another paging group by updating itslocation. However, the BS 2 provides the FCC 1, so that it is preferablethat the MS switches a paging group to another paging group B having thePG ID (B) supported by the FCC 1. Needless to say, the MS may performthe location update and the carrier switching at the same time. The MSmay receive a paging message through the FCC 1.

FIG. 11 is a conceptual diagram illustrating a method for enabling anidle mode MS to receive a paging message when the idle mode MS movesbetween BSs supporting multiple carriers (multi-carrier) according toyet another embodiment of the present invention.

FIG. 11 is a conceptual diagram illustrating an exemplary case in whichthe idle mode MS performs location update and carrier switching at thesame time.

Multi-carriers supplied from the SBS (BS 1) shown in FIG. 11 are equalto those of FIG. 8. Also, multi-carriers supplied from the NBS (BS 2)may be equal to those of the SBS (BS 1). However, it is assumed thatmulti-carriers and supplied from the NBS (BS 2) and PG IDs thereof aredifferent from those of the SBS (BS 1).

Referring to FIG. 11, the PG ID assigned to an idle mode MS is the PG ID(A), and the idle mode MS may move from the BS 1 to the BS 2. The MS mayreceive a BCH including CCI from the BS 2 during the paging listeninginterval. Therefore, the MS recognizes the CCI contained in the BCH (SeeTables 1 and 2), such that it can recognize PG IDs of FCCs supplied fromthe BS 2.

The BS 2 does not provide a PG ID (A) and the FCC supporting the PG ID(A). Therefore, the MS performs location update to the BS 2 (i.e.,switching from the paging group A to the paging group B), and at thesame time performs carrier switching.

Now a description will be made of an MS and a BS (macro BS (MBS) orfemto BS (FBS)) for implementing the above-described exemplaryembodiments of the present invention, according to an exemplaryembodiment of the present invention.

The MS may operate as a transmitter on an uplink and as a receiver on adownlink, while the BS may operate as a receiver on the uplink and as atransmitter on the downlink. That is, each of the MS and the BS mayinclude a transmitter and a receiver for transmission and reception ofinformation or data.

The transmitter and the receiver may include processors, modules, parts,and/or means for implementing the exemplary embodiments of the presentinvention. Especially, the transmitter and the receiver may include amodule (means) for encrypting messages, a module for interpretingencrypted messages, an antenna for transmitting and receiving messages,etc. An example of the transmitter and the receiver will be describedbelow with reference to FIG. 12.

FIG. 12 is a block diagram of a transmitter and a receiver according toan exemplary embodiment of the present invention.

Referring to FIG. 12, the left part corresponds to the transmitter andthe right part corresponds to the receiver. Each of the transmitter andthe receiver may include an antenna 1200 or 1201, a processor 1202 or1203, a Transmission (Tx) module 1205 or 1204, a Reception (Rx) module1207 or 1206, and a memory 1209 or 1208. The components of thetransmitter are the counter parts of those of the receiver. Thecomponents of the transmitter and the receiver will be described belowin more detail.

The antennas 1200 and 1201 include Tx antennas for transmitting signalsgenerated from Tx modules 1205 and 1204 and Rx antennas for receivingradio frequency (RF) signals and providing the received RF signals tothe Rx modules 1207 and 1206. If Multiple Input Multiple Output (MIMO)is supported, two or more antennas may be provided.

The processors 1202 and 1203 generally provide overall control to thetransmitter and the receiver, respectively. Especially, the processors1202 and 1203 may perform a control function for implementing theabove-described exemplary embodiments of the present invention, avariable MAC frame control function based on service characteristics anda propagation environment, a handover function, an authentication andencryption function, etc.

Particularly, the processor of the MS may perform location update orcarrier switching between BSs on the basis of multi-carrierconfiguration information according to the exemplary embodiments of thepresent invention.

For example, the idle mode MS according to embodiments of the presentinvention receives a first CCI including at least one multi-carrierconfiguration information from the serving BS (SBS) via a reception (Rx)antenna, and receives a second CCI from a neighboring BS (NBS). Thefirst CCI or the second CCI may include multi-carrier indexes and paginggroup IDs supported by respective multi-carriers.

In this case, the processor of the MS may perform location update to theneighboring BS (NBS) on the condition that the NBS does not support thepaging group ID that has been assigned to the MS from the serving BS(SBS). Also, in the case where the neighboring BS (NBS) does not providethe carrier currently used by the MS, the process of the MS may switchthe current carrier to one of multiple carriers supported by the NBS.

Meanwhile, the processor of the BS may perform scheduling byinterpreting a MAC message or data received from the MS, allocatingrequired uplink resources to the MS, generating an uplink grant carryinginformation about the resource allocation to the MS, and transmittingthe uplink grant to the MS. In addition, the processor of the BS mayreceive a message including an ID required for the MS, such as a STationIdentifier (STID), a Flow ID (FID), etc. from another processor orgenerate it, and then transmit it to the MS. Or the processor of the BSmay transmit a super frame header, including a field indicating a frameat which a message including CCI is transferred, to the MS. In addition,the processor of the BS may transmit a message including the CCI to theMS via the frame indicated by the above field.

The Tx modules 1205 and 1204 may encode and modulate transmission datascheduled by the processors 1202 and 1203 in a predetermined coding andmodulation scheme and provide the modulated data to the antennas 1200and 1201. Each pair of the Tx module 1205 and the antenna 1200, and theTx module 1204 and the antenna 1201 may be shown to be incorporated intoa single transmission part, while shown separately in FIG. 12.

The Rx modules 1207 and 1206 may recover original data by demodulatingand decoding data received through the antennas 1200 and 1201 andprovide the recovered data to the processors 1202 and 1203. Each pair ofthe Rx module 1207 and the antenna 1200, and the Rx module 1206 and theantenna 1201 may be shown to be incorporated into a single receptionpart, while shown separately in FIG. 12.

The memories 1209 and 1208 may store programs for processing and controlof the processors 1202 and 1203 and temporarily store input/output data(on the side of the MS, an uplink grant received from the BS, systeminformation, an STID, an FID, an action time, etc.). Each of thememories 1209 and 1208 may include at least one of storage media typessuch as a flash memory type, a hard disk type, a multimedia card microtype, a card-type memory (e.g. a Secure Digital (SD) or eXtreme Digital(XD) memory), a Random Access Memory (RAM), a Static Random AccessMemory (SRAM), a Read-Only Memory (ROM), an Electrically ErasableProgrammable Read-Only Memory (EEPROM), a Programmable Read-Only Memory,a magnetic memory, a magnetic disc, an optical disc, etc.

In the mean time, the BS may perform a control function for implementingthe above-described exemplary embodiments of the present invention,Orthogonal Frequency Division Multiple Access (OFDMA) packet scheduling,Time Division Duplex (TDD) packet scheduling and channelization, avariable MAC frame control function based on service characteristics anda propagation environment, a real-time high-speed traffic controlfunction, a handover function, an authentication and encryptionfunction, a packet modulation/demodulation function for datatransmission and reception, a high-speed packet channel coding function,a real-time MODEM control function, etc., by at least one of theabove-described modules, or the BS may further include an additionalmodule, part or means for performing these functions.

Mode for the Invention

Various embodiments have been described in the best mode for carryingout the invention.

INDUSTRIAL APPLICABILITY

The exemplary embodiments of the present invention are applicable tovarious wireless access systems. For example, the wireless accesssystems are a 3GPP system, a 3GPP2 system, and/or an IEEE 802.xx system.Besides the wireless access systems, the exemplary embodiments of thepresent invention are applicable to all technical fields in which thewireless access systems find their applications.

Those skilled in the art will appreciate that the present invention maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent invention. The above exemplary embodiments are therefore to beconstrued in all aspects as illustrative and not restrictive. The scopeof the invention should be determined by the appended claims and theirlegal equivalents, not by the above description, and all changes comingwithin the meaning and equivalency range of the appended claims areintended to be embraced therein. Also, it is obvious to those skilled inthe art that claims that are not explicitly cited in each other in theappended claims may be presented in combination as an exemplaryembodiment of the present invention or included as a new claim by asubsequent amendment after the application is filed.

The invention claimed is:
 1. A method for performing a paging procedurein a wireless access system supporting multiple carriers, the methodcomprising: receiving by a Mobile Station (MS), from a first BaseStation (BS), a Super Frame Header (SFH) including a Start Frame Number(SFN) field that indicates an index of a frame at which systeminformation is transmitted, the system information including firstcarrier configuration information (CCI) corresponding to a first set ofmultiple carriers currently supported by the first BS; receiving by theMS, from the first BS, second CCI at a first downlink frame at which apaging listening interval of the MS begins, the second CCI correspondingto a second set of multiple carriers supported by a second BS;determining whether to perform a location update and carrier switchingusing the first CCI and the second CCI when the MS moves from the firstBS to the second BS; and performing, by the MS, a paging procedure withthe second BS based on a paging message received from the second BS,wherein the first CCI includes indexes of the first set of multiplecarriers and a paging group ID supported by each carrier of the firstset of multiple carriers, and wherein the second CCI includes indexes ofthe second set of multiple carriers and a paging group ID supported byeach carrier of the second set of multiple carriers.
 2. The methodaccording to claim 1, wherein: the first BS is a Serving BS; and thesecond BS is a Neighboring BS.
 3. The method according to claim 1,further comprising: performing, by the MS, the location update to thesecond BS when the second BS does not provide, in the second CCI, apaging group ID assigned to the MS.
 4. The method according to claim 1,further comprising: performing, by the MS, the carrier switching to oneof the multiple carriers supported by the second BS when the second BSdoes not support a carrier currently used by the MS.
 5. A Mobile Station(MS) in a wireless access system supporting multiple carriers, the MScomprising: a receiver configured for: receiving an external radiosignal; receiving a Super Frame Header (SFH) from a first Base Station(BS), the SFH including a Start Frame Number (SFN) field that indicatesan index of a frame at which system information is transmitted, thesystem information including first carrier configuration information(CCI) corresponding to a first set of multiple carriers currentlysupported by the first BS; and receiving, from the first BS, second CCIat a first downlink frame at which a paging listening interval of the MSbegins, the second CCI corresponding to a second set of multiplecarriers supported by a second BS; and a processor configured for:determining whether to perform a location update and carrier switchingusing the first CCI and the second CCI when the MS moves from the firstBS to the second BS; and performing a paging procedure with the secondBS based on a paging message received from the second BS, wherein thefirst CCI includes indexes of the first set of multiple carriers and apaging group ID supported by each carrier of the first set of multiplecarriers, and wherein the second CCI includes indexes of the second setof multiple carriers and a paging group ID supported by each carrier ofthe second set of multiple carriers.
 6. The mobile station according toclaim 5, wherein the processor is further configured for performing thelocation update to the second BS when the second BS does not provide, inthe second CCI, a paging group ID assigned to the MS.
 7. The mobilestation according to claim 5, wherein the processor is furtherconfigured for performing the carrier switching to one carrier of themultiple carriers supported by the second BS when the second BS does notprovide a carrier currently used by the MS.
 8. The mobile stationaccording to claim 5, wherein: the first BS is a Serving BS; and thesecond BS is a Neighboring BS.